Simple Explanation (ELI5)

Think of a trailer like a boat on a river: the lighter the boat and the stronger the engine, the less water (fuel) you waste. Bigger batteries in electric trailers act like lighter boats and stronger motors, cutting CO₂ emissions.

Key Advantages & Current Limits

🟢 Pros: Can cut emissions by up to 40% with large batteries and electric axles. 🟢 Pros: Helps meet EU targets (10% for semitrailers, 7.5% for trailers by 2030). 🔴 Cons: Higher price and extra battery weight may slow adoption. 🔴 Cons: Savings depend on battery size and vehicle design; without optimisation the benefit is limited.

Future Outlook & Takeaways

In the next 3‑5 years VECTO Trailer will be updated to accurately assess electric trailers, showing real energy savings. This will make it easier to adopt e‑trailers, lowering costs and helping cleaner roads.

E‑trailers: Can Electric Trailers Really Cut Emissions?

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Since January 1, 2024, new heavy‑duty trailers must prove their CO₂ emissions and fuel use. They are tested with VECTO Trailer, a software that mixes trailer data (mass, aerodynamics, rolling resistance) with a standard towing vehicle. The results help meet EU rules that demand a 10 % cut for semitrailers and 7.5 % for trailers by 2030 compared with 2025.

Now the same approach is being extended to electric trailers—those with an electric axle or electric auxiliaries powered by a battery. Researchers simulated several cases: trailers with small batteries (5‑50 kWh) for electric refrigeration cut CO₂ by 5‑10 %, while those with larger batteries (50‑500 kWh) and e‑axles (50‑500 kW) can reduce emissions up to 40 %.

Battery size is the main driver: the bigger the battery, the larger the saving. Yet market uptake is uncertain. Trailers outnumber towing trucks, and the higher price of the more powerful e‑trailers could slow adoption. Time will tell if the industry embraces electric trailers to greener our roads.

Bonus

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The VECTO Trailer model relies on a closed‑loop dynamic simulation where the towing vehicle is represented by an average European consumption profile (weight, power, aerodynamic drag). For electric trailers, the software adds an energy balance that accounts for: 1) electric power required for propulsion assistance (e‑axle), 2) auxiliary consumption (refrigeration, lighting, safety systems) and 3) conversion losses (inverter, wiring). Battery capacity influences both the trailer’s own weight, increasing rolling resistance, and the available energy for auxiliary propulsion.

Simulations used typical e‑axle efficiency curves (70‑85 % efficiency) and variable load profiles (full load, empty, acceleration). Electric range extension is calculated by subtracting the power supplied by the e‑axle from the fuel consumption of the towing truck, considering the battery’s residual capacity. A “market penetration” factor was also introduced to modulate average emission impact based on the share of e‑trailers in use. Results show that for batteries above 200 kWh, average emission reduction exceeds 30 % only if the e‑axle is sized at 300 kW or more, providing sufficient torque to assist during climbs. However, the mass increase (≈ 200 kg per 100 kWh) can erode part of the benefit, making lightweight structures (advanced materials, aerodynamic design) essential. These parameters will be integrated into the next VECTO Trailer release, enabling more precise assessments for advanced electric mobility scenarios.